/*
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 * and open the template in the editor.
 */
package main;

import javax.swing.*;
import java.awt.*;

class Testing extends JFrame {

    JComboBox cbo = new JComboBox();

    public Testing() {
        setLocation(400, 300);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        cbo.setRenderer(new MyRenderer());
        getContentPane().add(cbo);
        for (int x = 1; x < 100; x += 3) {
            cbo.addItem(new String[]{"" + x, "" + (x + 1), "" + (x + 2)});
        }
        pack();

    }

    public static void main(String[] args) {
        new Testing().setVisible(true);
    }
}

class MyRenderer extends JPanel implements ListCellRenderer {

    JLabel[] lbl = new JLabel[3];

    public MyRenderer() {
        setLayout(new GridLayout(0, 3));
        for (int x = 0; x < lbl.length; x++) {
            lbl[x] = new JLabel();
            lbl[x].setOpaque(true);
            add(lbl[x]);
        }
    }

    public Component getListCellRendererComponent(JList list, Object value,
            int index, boolean isSelected, boolean cellHasFocus) {
        for (int x = 0; x < lbl.length; x++) {
            lbl[x].setText((String) ((String[]) value)[x]);
        }
        return this;
    }
}
